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Carlsson N, Arestedt K, Alvariza A, Axelsson L, Bremer A. Factors associated with symptoms of prolonged grief among bereaved family members of persons who died from sudden cardiac arrest. Eur J Cardiovasc Nurs 2021. [DOI: 10.1093/eurjcn/zvab060.088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Public Institution(s). Main funding source(s): Linnaeus University, Sweden
Background
High incidence and mortality make cardiac arrest one of the leading causes of death in western countries. Death from sudden cardiac arrest implies a stressful and challenging situation for bereaved family members with increased risk for prolonged grief disorder. This serious disorder needs to be identified and treated.
Purpose
To explore factors associated with symptoms of prolonged grief among bereaved family members of persons who died from sudden cardiac arrest.
Methods
This cross-sectional observational study was based on a questionnaire to bereaved family members six month after the death. Background questions about the family member and the loss, the Prolonged Grief disorder instrument (PG-13) and the Multidimensional Scale of Perceived Social Support (MSPSS) were included and analyzed using univariate and multiple linear regression.
Results
This study included 108 family members who were adult children (n = 55, 51%), spouse (n = 36, 33%), or significant others (n = 17, 16%) to a person that died of sudden cardiac arrest. The mean age of the family members was 61 years (range 25-87), most were women (n = 74, 69%), and did not have a university degree (n = 74, 69%). A majority of the cardiac arrests took place out of hospital (n = 59, 81%). One third of the family members were present during the resuscitation (n = 35, 32%). A minority was offered professional support from the healthcare service (n = 93, 86%) and few sought healthcare for problems in relation to the loss (n = 19, 18%) and/or received professional support from a psychologist or equivalent (n = 16, 15%).
In total, 18% (n = 19) reported symptoms of prolonged grief and the prevalence was even higher among spouses (n = 10, 29%). In the univariate regression models, being a spouse of the deceased (B = 6.34, p = 0.004, R2 = 0.08), sought healthcare related to the loss (B = 10.51, p < 0.001, R2 = 0.15), offered support from the healthcare related to the loss (B = 6.28, p = 0.030, R2 = 0.05), received professional support for the loss (B = 7.30, p = 0.011, R2 = 0.06), and lower levels of perceived social support (B=-0.28, p < 0.001, R2 = 0.16) were significantly associated with higher levels of symptoms of prolonged grief. All these variables, except offered support from the healthcare, were still significant in the multiple regression model and explained 35% of the total variance in PG-13 (F(4, 96)=12.96, p < 0.001). Age, sex, education, and presence during resuscitation were not significantly associated with symptoms of prolonged grief in any of the regression models.
Conclusion
Prolonged grief is a significant problem in bereaved family members of persons who died from sudden cardiac arrest, particularly in spouses, those in need of professional support from the healthcare, and those with low social support. Bereavement support should be offered to reduce the risk to developing prolonged grief after unsuccessful resuscitation and sudden death from cardiac arrest.
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Affiliation(s)
| | | | - A Alvariza
- Ersta SkÇôndal University College, Stockholm, Sweden
| | | | - A Bremer
- Linnaeus University, Kalmar, Sweden
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Tzimorotas D, Afseth NK, Lindberg D, Kjørlaug O, Axelsson L, Shapaval V. Pretreatment of different food rest materials for bioconversion into fungal lipid-rich biomass. Bioprocess Biosyst Eng 2018; 41:1039-1049. [PMID: 29654357 PMCID: PMC6013528 DOI: 10.1007/s00449-018-1933-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 04/01/2018] [Indexed: 11/10/2022]
Abstract
Food rest materials have the potential to be used as media components in various types of fermentations. Oleaginous filamentous fungi can utilize those components and generate a high-value lipid-rich biomass, which could be further used for animal and human use. One of the main limitations in this process is the pretreatment of food rest materials, needed to provide homogenization, sterilization and solubilization. In this study, two pretreatment processes-steam explosion and enzymatic hydrolysis-were evaluated for potato and animal protein-rich food rest materials. The pretreated food rest materials were used for the production of fungal lipid-rich biomass in submerged fermentation by the oleaginous fungus Mucor circinelloides. Cultivation media based on malt extract broth and glucose were used as controls of growth and lipid production, respectively. It was observed that media based on food rest materials can support growth and lipid production in M. circinelloides to a similar extent as the control media. More specifically, the use of potato hydrolysate combined with chicken auto-hydrolysate resulted in a higher fungal total biomass weight than using malt extract broth. When the same C/N ratio was used for glucose and rest materials-based media, similar lipid content was obtained or even higher using the latter media.
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Affiliation(s)
| | | | | | | | | | - V Shapaval
- Nofima AS, 1430, Ås, Norway
- The Faculty of Science and Technology, Norwegian University of Life Sciences, 1432, Ås, Norway
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Alakomi HL, Höhl A, Horvatek Tomic D, Thomas M, Bruggeman G, Tassis P, Prukner-Radovcic E, Tzika E, Axelsson L, Kneifel W, Saarela M. Antimicrobial resistance and residues in the EU: current situation and possible countermeasures, emphasis on Campylobacterand Salmonella. Quality Assurance and Safety of Crops & Foods 2016. [DOI: 10.3920/qas2014.0576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- H.-L. Alakomi
- VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, 02044 VTT, Finland
| | - A. Höhl
- Department of Food Science and Technology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - D. Horvatek Tomic
- Department of Poultry Diseases with Clinic, Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, 10000 Zagreb, Croatia
| | - M. Thomas
- Fera Science Ltd., Sand Hutton, YO41 1LZ York, United Kingdom
| | - G. Bruggeman
- Nutrition Sciences N.V., Booiebos 5, 9031 Drongen, Belgium
| | - P. Tassis
- Farm Animals Clinic, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, St. Voutyra 11, 54627 Thessaloniki, Greece
| | - E. Prukner-Radovcic
- Department of Poultry Diseases with Clinic, Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, 10000 Zagreb, Croatia
| | - E. Tzika
- Farm Animals Clinic, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, St. Voutyra 11, 54627 Thessaloniki, Greece
| | | | - W. Kneifel
- Department of Food Science and Technology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - M. Saarela
- VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, 02044 VTT, Finland
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Axelsson L, Holck A, Rud I, Samah D, Tierce P, Favre M, Kure CF. Cleaning of conveyor belt materials using ultrasound in a thin layer of water. J Food Prot 2013; 76:1401-7. [PMID: 23905796 DOI: 10.4315/0362-028x.jfp-12-563] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cleaning of conveyor belts in the food industry is imperative for preventing the buildup of microorganisms that can contaminate food. New technologies for decreasing water and energy consumption of cleaning systems are desired. Ultrasound can be used for cleaning a wide range of materials. Most commonly, baths containing fairly large amounts of water are used. One possibility to reduce water consumption is to use ultrasonic cavitation in a thin water film on a flat surface, like a conveyor belt. In order to test this possibility, a model system was set up, consisting of an ultrasound transducer/probe with a 70-mm-diameter flat bottom, operating at 19.8 kHz, and contaminated conveyor belt materials in the form of coupons covered with a thin layer of water or water with detergent. Ultrasound was then applied on the water surface at different power levels (from 46 to 260 W), exposure times (10 and 20 s), and distances (2 to 20 mm). The model was used to test two different belt materials with various contamination types, such as biofilms formed by bacteria in carbohydrate- or protein-fat-based soils, dried microorganisms (bacteria, yeasts, and mold spores), and allergens. Ultrasound treatment increased the reduction of bacteria and yeast by 1 to 2 log CFU under the most favorable conditions compared with water or water-detergent controls. The effect was dependent on the type of belt material, the power applied, the exposure time, and the distance between the probe and the belt coupon. Generally, dried microorganisms were more easily removed than biofilms. The effect on mold spores was variable and appeared to be species and material dependent. Spiked allergens were also efficiently removed by using ultrasound. The results in this study pave the way for new cleaning designs for flat conveyor belts, with possibilities for savings of water, detergent, and energy consumption.
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Affiliation(s)
- L Axelsson
- Nofima-Norwegian Institute of Food Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway.
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Heir E, Holck AL, Omer MK, Alvseike O, Måge I, Høy M, Rode TM, Sidhu MS, Axelsson L. Effects of post-processing treatments on sensory quality and Shiga toxigenic Escherichia coli reductions in dry-fermented sausages. Meat Sci 2013; 94:47-54. [PMID: 23376436 DOI: 10.1016/j.meatsci.2012.12.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 12/21/2012] [Accepted: 12/29/2012] [Indexed: 11/19/2022]
Abstract
The effects of post-processing treatments on sensory quality and reduction of Shiga toxigenic Escherichia coli (STEC) in three formulations of two types of dry-fermented sausage (DFS; salami and morr) were evaluated. Tested interventions provided only marginal changes in sensory preference and characteristics. Total STEC reductions in heat treated DFS (32°C, 6days or 43°C, 24h) were from 3.5 to >5.5 log from production start. Storing of sausages (20°C, 1month) gave >1 log additional STEC reduction. Freezing and thawing of sausages in combination with storage (4°C, 1month) gave an additional 0.7 to 3.0 log reduction in STEC. Overall >5.5 log STEC reductions were obtained after storage and freezing/thawing of DFS with increased levels of glucose and salt. This study suggests that combined formulation optimisation and post-process strategies should be applicable for implementation in DFS production to obtain DFS with enhanced microbial safety and high sensory acceptance and quality.
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Affiliation(s)
- E Heir
- Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, N-1431 Ås, Norway.
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Alvarez-Ordóñez A, Alvseike O, Omer MK, Heir E, Axelsson L, Holck A, Prieto M. Heterogeneity in resistance to food-related stresses and biofilm formation ability among verocytotoxigenic Escherichia coli strains. Int J Food Microbiol 2012; 161:220-30. [PMID: 23337122 DOI: 10.1016/j.ijfoodmicro.2012.12.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 09/26/2012] [Accepted: 12/02/2012] [Indexed: 01/14/2023]
Abstract
This study assessed the resistance of ten verocytotoxigenic Escherichia coli (VTEC) isolates of commonly encountered serogroups/-types and two non-pathogenic E. coli strains to various food-related stresses (acid, alkaline, heat and high hydrostatic pressure treatments) and their biofilm formation ability. In addition, the global changes in the cellular composition in response to the exposure to these adverse environments were monitored by Fourier Transform Infrared (FT-IR) spectroscopy for two of the strains. Large inter-strain variations in stress resistance were observed. The most tolerant strains belonged to serogroup O157 which included both the O157:H7 type strain EDL933 and a representative isolate of the sorbitol fermenting O157:H- VTEC clone (strain MF3582). Strain C-600, a non-pathogenic laboratory strain, was sensitive to multiple stresses. Although wide variation in biofilm-forming ability was observed among VTEC isolates, no consistent relationships between biofilm-forming ability and capacity to withstand stress exposures were found. Analysis of the allelic status of the rpoS gene, involved in the general stress response of stationary-phase cells, allowed detection of loss-of-function mutations for two strains, E218/02 and MF2411, both of them showing as common features a high sensitivity to alkaline and heat treatments and a poor ability to form mature biofilms. Evidences found in this study confirm rpoS as a highly mutable gene in nature, and suggest its relevance not only for the mount of an active stress response but also for the establishment of mature biofilm communities. Our findings contribute to increase the knowledge on the resistance of VTEC to environmental stresses commonly encountered in the food chain, which can lead to improved strategies for preventing VTEC infections.
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Affiliation(s)
- A Alvarez-Ordóñez
- Department of Food Hygiene and Technology, University of León, Campus de Vegazana, E-24071 León, Spain.
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Omer M, Alvseike O, Holck A, Axelsson L, Prieto M, Skjerve E, Heir E. Application of high pressure processing to reduce verotoxigenic E. coli in two types of dry-fermented sausage. Meat Sci 2010; 86:1005-9. [DOI: 10.1016/j.meatsci.2010.08.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 02/18/2010] [Accepted: 08/17/2010] [Indexed: 10/19/2022]
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Heir E, Holck AL, Omer MK, Alvseike O, Høy M, Måge I, Axelsson L. Reduction of verotoxigenic Escherichia coli by process and recipe optimisation in dry-fermented sausages. Int J Food Microbiol 2010; 141:195-202. [PMID: 20626098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Outbreaks of verotoxigenic Escherichia coli (VTEC) linked to dry-fermented sausages (DFSs) have emphasized the need for DFS manufacturers to introduce measures to obtain enhanced safety and still maintain the sensory qualities of their products. To our knowledge no data have yet been reported on non-O157:H7 VTEC survival in DFS. Here, the importance of recipe and process variables on VTEC (O157:H7 and O103:H25) reductions in two types of DFS, morr and salami, was determined through three statistically designed experiments. Linear regression and ANOVA analyses showed that no single variable had a dominant effect on VTEC reductions. High levels of NaCl, NaNO(2), glucose (low pH) and fermentation temperature gave enhanced VTEC reduction, while high fat and large casing diameter (a(w)) gave the opposite effect. Interaction effects were small. The process and recipe variables showed similar effects in morr and salami. In general, recipes combining high batter levels of salt (NaCl and NaNO(2)) and glucose along with high fermentation temperature that gave DFS with low final pH and a(w), provided approximately 3 log(10) reductions compared to approximately 1.5 log(10) reductions obtained for standard recipe DFS. Storage at 4 degrees C for 2 months provided log(10) 0.33-0.95 additional VTEC reductions and were only marginally affected by recipe type. Sensory tests revealed only small differences between the various recipes of morr and salami. By optimisation of recipe and process parameters, it is possible to obtain increased microbial safety of DFS while maintaining the sensory qualities of the sausages.
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Affiliation(s)
- E Heir
- Nofima Mat AS, Osloveien, As, Norway.
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Ford C, Tuomela J, Hedditch E, Axelsson L, Liu Q, Ward R, Härkönen P, Andersson T. 43 Estrogen receptor alpha is upregulated and metastasis inhibited in a murine breast cancer model following treatment with the novel Wnt-5a derived-hexapeptide, Foxy-5. EJC Suppl 2010. [DOI: 10.1016/s1359-6349(10)70852-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Heir E, Holck AL, Omer MK, Alvseike O, Høy M, Måge I, Axelsson L. Reduction of verotoxigenic Escherichia coli by process and recipe optimisation in dry-fermented sausages. Int J Food Microbiol 2010; 141:S0168-1605(10)00294-1. [PMID: 20965097 DOI: 10.1016/j.ijfoodmicro.2010.05.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 05/10/2010] [Accepted: 05/14/2010] [Indexed: 11/15/2022]
Abstract
Outbreaks of verotoxigenic Escherichia coli (VTEC) linked to dry-fermented sausages (DFSs) have emphasized the need for DFS manufacturers to introduce measures to obtain enhanced safety and still maintain the sensory qualities of their products. To our knowledge no data have yet been reported on non-O157:H7 VTEC survival in DFS. Here, the importance of recipe and process variables on VTEC (O157:H7 and O103:H25) reductions in two types of DFS, morr and salami, was determined through three statistically designed experiments. Linear regression and ANOVA analyses showed that no single variable had a dominant effect on VTEC reductions. High levels of NaCl, NaNO(2), glucose (low pH) and fermentation temperature gave enhanced VTEC reduction, while high fat and large casing diameter (a(w)) gave the opposite effect. Interaction effects were small. The process and recipe variables showed similar effects in morr and salami. In general, recipes combining high batter levels of salt (NaCl and NaNO(2)) and glucose along with high fermentation temperature that gave DFS with low final pH and a(w), provided approximately 3 log(10) reductions compared to approximately 1.5 log(10) reductions obtained for standard recipe DFS. Storage at 4°C for 2months provided log(10) 0.33-0.95 additional VTEC reductions and were only marginally affected by recipe type. Sensory tests revealed only small differences between the various recipes of morr and salami. By optimisation of recipe and process parameters, it is possible to obtain increased microbial safety of DFS while maintaining the sensory qualities of the sausages.
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Affiliation(s)
- E Heir
- Nofima Mat AS, Osloveien 1, N-1430 Ås, Norway
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Olstorpe M, Axelsson L, Schnürer J, Passoth V. Effect of starter culture inoculation on feed hygiene and microbial population development in fermented pig feed composed of a cereal grain mix with wet wheat distillersâ grain. J Appl Microbiol 2010; 108:129-38. [DOI: 10.1111/j.1365-2672.2009.04399.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Chung TC, Axelsson L, Lindgren SE, Dobrogosz WJ. In VitroStudies on Reuterin Synthesis byLactobacillus reuteri. Microbial Ecology in Health and Disease 2009. [DOI: 10.3109/08910608909140211] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- T. C. Chung
- Department of Microbiology, North Carolina State University, Raleigh, NC, USA
| | - L. Axelsson
- The Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - S. E. Lindgren
- The Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - W. J. Dobrogosz
- Department of Microbiology, North Carolina State University, Raleigh, NC, USA
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Bergenfeldt M, Axelsson L, Ohlsson K. Release of neutrophil proteinase 4(3) and leukocyte elastase during phagocytosis and their interaction with proteinase inhibitors. Scandinavian Journal of Clinical and Laboratory Investigation 2009; 52:823-9. [PMID: 1362620 DOI: 10.3109/00365519209088387] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Neutrophil proteinase 4 (NP4) is a major neutral proteinase of the human polymorphonuclear (PMN) leukocyte, which is present in amounts similar to leukocyte elastase. NP4(3) is a potent, non-specific proteinase, which may degrade structural and soluble proteins in the tissues and body fluids, and it has been implicated as an important pathogenetic factor in lung emphysema. We have studied the release of elastase and NP4(3) in an in vitro model of phagocytosis. alpha 1-proteinase inhibitor (alpha 1-PI) is the major plasma inhibitor of both leukocyte elastase and NP4(3), but alpha 1-PI bound leukocyte elastase more readily than NP4(3). The basic conditions were designed so that some proteolytic activity was present in the medium. Addition of increasing amounts of Secretory leukocyte protease inhibitor (SLPI) to the incubation mixtures resulted in binding of leukocyte elastase to this inhibitor and extinction of free proteolytic activity against both natural and synthetic substrates. The progressive binding of leukocyte elastase to SLPI instead of alpha 1-PI was paralleled by an increasing binding of NP4(3) to alpha 1-PI. SLPI is a potent inhibitor of leukocyte elastase and cathepsin G, and although it lacks inhibitory effect on NP4(3), it may obviously indirectly aid in the binding and inhibition of NP4(3) to alpha 1-PI, by taking care of at least part of the leukocyte elastase. As a specific NP4(3)-inhibitor is not readily available for therapeutic use, this effect may prove useful under in vivo conditions and enhance the protective effect of administered recombinant human SLPI.
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Affiliation(s)
- M Bergenfeldt
- Department of Surgery, Lund University, Malmö General Hospital, Sweden
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Mathiesen G, Sveen A, Piard JC, Axelsson L, Eijsink VGH. Heterologous protein secretion by Lactobacillus plantarum using homologous signal peptides. J Appl Microbiol 2008; 105:215-26. [PMID: 18298538 DOI: 10.1111/j.1365-2672.2008.03734.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To test seven selected putative signal peptides from Lactobacillus plantarum WCFS1 in terms of their ability to drive secretion of two model proteins in Lact. plantarum, and to compare the functionality of these signal peptides with that of well-known heterologous signal peptides (Usp45, M6). METHODS AND RESULTS Signal peptide functionality was assessed using a series of modular derivatives of the pSIP vectors for peptide pheromone-controlled high-level gene expression in lactobacilli. Several of the constructs with homologous signal peptides yielded similar or higher reporter protein activities than constructs with heterologous signal peptides. Two of the homologous signal peptides (Lp_0373 and Lp_0600) appeared as especially promising candidates for directing secretion, as they were among the best performing with both reporter proteins. CONCLUSIONS We have identified homologous signal peptides for high-level secretion of heterologous proteins in Lact. plantarum. With the model proteins, some of these performed better than commonly used heterologous signal peptides. SIGNIFICANCE AND IMPACT OF THE STUDY The homologous signal peptides tested out, in this study, could be useful in food-grade systems for secretion of interesting proteins in Lact. plantarum. The constructed modular secretion vectors are easily accessible for rapid signal peptide screening.
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Affiliation(s)
- G Mathiesen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, As, Norway.
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16
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Abstract
Bovine peripheral blood lymphocytes (PBL) were isolated from blood collected from 6 cattle. After treatment with neuraminidase, 40 or 60% of the cells were shown to combine with Helix Pomatia A hemagglutinin (HP) depending whether a direct or indirect fluorescence technique was used. About 20% of the cells were Ig-bearing. With double staining fluorescence technique, it was shown that cells attaching to HP were not Ig-bearing and the reverse. With the aid of HP, covalently bound to Sepharose, Ig-bearing cells could be separated from cell populations attaching to HP. The fraction of cells forming rosettes with sheep erythrocytes was proportional to that of HP attaching cells both before and after fractionation on the HP column. It is therefore concluded that HP is a marker for bovine T-cells, and that this lectin may be used to separate B-cells from T-cells.
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Affiliation(s)
- B Morein
- Department of Biological Products, The National Veterinary Institute, Stockholm, Sweden
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Mathiesen G, Sørvig E, Blatny J, Naterstad K, Axelsson L, Eijsink VGH. High-level gene expression in Lactobacillus plantarum using a pheromone-regulated bacteriocin promoter. Lett Appl Microbiol 2004; 39:137-43. [PMID: 15242451 DOI: 10.1111/j.1472-765x.2004.01551.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS To use promoters and regulatory genes involved in the production of the bacteriocin sakacin P to obtain high-level regulated gene expression in Lactobacillus plantarum. METHODS AND RESULTS In a plasmid containing all three operons naturally involved in sakacin P production, the genes encoding sakacin P and its immunity protein were replaced by the aminopeptidase N gene from Lactococcus lactis (pepN) or the beta-glucuronidase gene from Escherichia coli (gusA). The new genes were precisely fused to the start codon of the sakacin P gene and the stop codon of the immunity gene. This set-up permitted regulated (external pheromone controlled) overexpression of both reporter genes in L. plantarum NC8. For PepN, production levels amounted to as much as 40% of total cellular protein. CONCLUSIONS Promoters and regulatory genes involved in production of sakacin P are suitable for establishing inducible high-level gene expression in L. plantarum. SIGNIFICANCE AND IMPACT OF THE STUDY This study describes a system for controllable gene expression in lactobacilli, giving some of the highest expression levels reported so far in this genus.
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Affiliation(s)
- G Mathiesen
- Department of Chemistry, Biotechnology and Food Science, Agricultural University of Norway, As, Norway
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18
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Abstract
AIMS To exploit promoters involved in production of the bacteriocin sakacin P for regulated overexpression of genes in Lactobacillus plantarum C11. METHODS AND RESULTS Production of sakacin P by Lact. sakei LTH673 is controlled by a peptide-based quorum sensing system that drives strong, regulated promoters. One of these promoters (PorfX) was used to establish regulated overexpression of genes encoding chloramphenicol acetyltransferase from Bacillus pumilus, aminopeptidase N from Lactococcus lactis or chitinase B from Serratia marcescens in Lact. plantarum C11, a strain that naturally possesses the regulatory machinery that is necessary for promoter activation. The expression levels obtained were highly dependent on which gene was used and on how the promoter was coupled to this gene. The highest expression levels (14% of total cellular protein) were obtained with the aminopeptidase N gene translationally fused to the regulated promoter. CONCLUSIONS Sakacin promoters permit regulated expression of a variety of genes in Lact. plantarum C11. SIGNIFICANCE AND IMPACT OF THE STUDY This study shows the usefulness of regulated bacteriocin promoters for developing new gene expression systems for lactic acid bacteria, in particular lactobacilli.
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Affiliation(s)
- G Mathiesen
- Department of Chemistry and Biotechnology, Agricultural University of Norway, As, Norway
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Affiliation(s)
- T. Møretrø
- MATFORSK, Norwegian Food Research Institute, A³s, Norway
| | - B. F. Hagen
- MATFORSK, Norwegian Food Research Institute, A³s, Norway
| | - L. Axelsson
- MATFORSK, Norwegian Food Research Institute, A³s, Norway
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20
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Abstract
AIM To develop an inducible gene expression system for Lactobacillus sakei, based on the regulatory system of sakacin A production. METHODS AND RESULTS A Lactobacillus/Escherichia coli shuttle vector; pKRV3, was constructed including the signal transducing system genes of the bacteriocin sakacin A. The gusA gene fused to PsapA promoter, cloned in this vector allowed for inducible beta-glucuronidase expression in L. sakei and L. plantarum following the addition of the sakacin A inducing peptide. PsapA appeared to be a strong and tightly controlled promoter when compared with known promoters. CONCLUSION The pKRV3 system can be used as an inducible gene expression system in lactobacilli. SIGNIFICANCE AND IMPACT OF THE STUDY A novel, inducible gene expression system has been developed for lactic acid bacteria relevant in food fermentations.
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Affiliation(s)
- L Axelsson
- MATFORSK, Norwegian Food Research Institute, Osloveien, Norway.
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21
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Katla T, Naterstad K, Vancanneyt M, Swings J, Axelsson L. Differences in susceptibility of Listeria monocytogenes strains to sakacin P, sakacin A, pediocin PA-1, and nisin. Appl Environ Microbiol 2003; 69:4431-7. [PMID: 12902226 PMCID: PMC169072 DOI: 10.1128/aem.69.8.4431-4437.2003] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2003] [Accepted: 05/27/2003] [Indexed: 11/20/2022] Open
Abstract
Two hundred strains of Listeria monocytogenes collected from food and the food industry were analyzed for susceptibility to the class IIa bacteriocins sakacin P, sakacin A, and pediocin PA-1 and the class I bacteriocin nisin. The individual 50% inhibitory concentrations (IC(50)) were determined in a microtiter assay and expressed in nanograms per milliliter. The IC(50) of sakacin P ranged from 0.01 to 0.61 ng ml(-1). The corresponding values for pediocin PA-1, sakacin A, and nisin were 0.10 to 7.34, 0.16 to 44.2, and 2.2 to 781 ng ml(-1), respectively. The use of a large number of strains and the accuracy of the IC(50) determination revealed patterns not previously described, and for the first time it was shown that the IC(50) of sakacin P divided the L. monocytogenes strains into two distinct groups. Ten strains from each group were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins and amplified fragment length polymorphism. The results from these studies essentially confirmed the grouping based on the IC(50) of sakacin P. A high correlation was found between the IC(50) of sakacin P and that of pediocin PA-1 for the 200 strains. Surprisingly, the correlation between the IC(50) of the two class IIa bacteriocins sakacin A and sakacin P was lower than the correlation between the IC(50) of sakacin A and the class I bacteriocin nisin.
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Affiliation(s)
- T Katla
- Matforsk, Norwegian Food Research Institute, N-1430 s., Norway
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22
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Katla T, Møretrø T, Sveen I, Aasen IM, Axelsson L, Rørvik LM, Naterstad K. Inhibition of Listeria monocytogenes in chicken cold cuts by addition of sakacin P and sakacin P-producing Lactobacillus sakei. J Appl Microbiol 2002; 93:191-6. [PMID: 12147066 DOI: 10.1046/j.1365-2672.2002.01675.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To evaluate the potential of sakacin P and sakacin P-producing Lactobacillus sakei for the inhibition of growth of Listeria monocytogenes in chicken cold cuts, by answering the following questions. (i) Is sakacin P actually produced in food? (ii) Is sakacin P produced in situ responsible for the inhibiting effect? (iii) How stable is sakacin P in food? METHODS AND RESULTS Listeria monocytogenes, a Lact. sakei strain and/or the bacteriocin sakacin P were added to chicken cold cuts, vacuum packed and incubated at 4 or 10 degrees C for 4 weeks. Each of two isogenic Lact. sakei strains, one producing sakacin P and the other not, had an inhibiting effect on the growth of L. monocytogenes. The effect of these two isogenic strains on the growth of L. monocytogenes was indistinguishable, even though sakacin P was produced in the product by one of the two Lact. sakei strains. The addition of purified sakacin P had an inhibiting effect on the growth of L. monocytogenes. A high dosage of sakacin P (3.5 microg x g(-1)) had a bacteriostatic effect throughout the storage period of 4 weeks, while a low dosage (12 ng x g(-1)) permitted initial growth, but at a slow rate. After 4 weeks of storage, the number of L. monocytogenes in the samples with a low dosage of sakacin P was 2 logs below that in the untreated control. When using a high dosage of sakacin P, the bacteriocin was detected in samples stored for up to 6 weeks. CONCLUSIONS (i) Sakacin P is produced by a Lact. sakei strain when growing on vacuum-packed chicken cold cuts. (ii) Inhibiting effects of Lact. sakei, other than sakacin P, are active in inhibiting the growth of L. monocytogenes growing on chicken cold cuts. (iii) Sakacin P is stable on chicken cold cuts over a period of 4 weeks. SIGNIFICANCE AND IMPACT OF THE STUDY Both sakacin P and Lact. sakei were found to have potential for use in the control of L. monocytogenes in chicken cold cuts.
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Affiliation(s)
- T Katla
- Matforsk, Norwegian Food Research Institute, As, Norway
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23
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Meister M, Markenroth K, Aleksandrov D, Aumann T, Axelsson L, Baumann T, Borge MJG, Chulkov LV, Dostal W, Eberlein B, Elze TW, Emling H, Forssén C, Geissel H, Hellström M, Holzmann R, Jonson B, Kratz JV, Kulessa R, Leifels Y, Leistenschneider A, Mukha I, Münzenberg G, Nickel F, Nilsson T, Nyman G, Richter A, Riisager K, Scheidenberger C, Schrieder G, Simon H, Tengblad O, Zhukov MV. Evidence for a new low-lying resonance state in 7He. Phys Rev Lett 2002; 88:102501. [PMID: 11909350 DOI: 10.1103/physrevlett.88.102501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2001] [Revised: 12/26/2001] [Indexed: 05/23/2023]
Abstract
Low-lying resonance states in 7He(6He+n), formed after fragmentation reactions of a 227 MeV/nucleon 8He beam on a carbon target, have been studied. Coincidences between 6He nuclei and neutrons, corresponding to the one-neutron knockout channel in 8He, were selected. The relative energy spectrum in the 6He+n system shows a structure, which is interpreted as the 7He ( Ipi = 3/2(-)) ground state, unbound with 0.43(2) MeV relative to the 6He+n system and a width of Gamma = 0.15(8) MeV overlapping with an excited ( Ipi = 1/2(-)) state observed at 1.0(1) MeV with a width of Gamma = 0.75(8) MeV.
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Affiliation(s)
- M Meister
- Experimentell Fysik, Chalmers Tekniska Högskola och Göteborgs Universitet, S-412 96 Göteborg, Sweden
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24
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Abstract
AIMS To study the germination and growth of both inoculated and naturally occurring Bacillus strains in heat-treated cream with and without nisin. METHODS AND RESULTS In heat-treated cream (90 degrees C for 15 min) stored at 8 degrees C, growth was dominated by naturally occurring Bacillus strains such as Bacillus pumilus and B. licheniformis. Only six of the 52 isolated strains were B. cereus/thuringiensis. All of the B. cereus strains, but none of the other strains, produced enterotoxin when tested with the TECRA and reverse passive latex agglutination kits. Bacterial growth during storage of the cream at 8 or 10 degrees C was completely inhibited by low concentrations of nisin. CONCLUSION The high number of Bacillus strains surviving the heat treatment represent a risk for heat-treated food that contains cream. The safety of the cream, for instance in "ready-to-eat" products, can be improved by the addition of low concentrations of nisin. SIGNIFICANCE AND IMPACT OF THE STUDY Spores of several Bacillus species may survive heat treatment of cream, but low concentration of nisin with inhibit germination and growth.
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Affiliation(s)
- H Nissen
- MATFORSK, Norwegian Food Research Institute, Oslovn. 1, N-1430 As, Norway.
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25
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Labiche M, Orr NA, Marqués FM, Angélique JC, Axelsson L, Benoit B, Bergmann UC, Borge MJ, Catford WN, Chappell SP, Clarke NM, Costa G, Curtis N, D'Arrigo A, de Góes Brennand E, Dorvaux O, Fazio G, Freer M, Fulton BR, Giardina G, Grévy S, Guillemaud-Mueller D, Hanappe F, Heusch B, Jones KL, Jonson B, Le Brun C, Leenhardt S, Lewitowicz M, Lopez MJ, Markenroth K, Mueller AC, Nilsson T, Ninane A, Nyman G, de Oliveira F, Piqueras I, Riisager K, Saint Laurent MG, Sarazin F, Singer SM, Sorlin O, Stuttgé L. Halo structure of (14)Be. Phys Rev Lett 2001; 86:600-603. [PMID: 11177891 DOI: 10.1103/physrevlett.86.600] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2000] [Indexed: 05/23/2023]
Abstract
The two-neutron halo nucleus (14)Be has been investigated in a kinematically complete measurement of the fragments ((12)Be and neutrons) produced in dissociation at 35 MeV/nucleon on C and Pb targets. Two-neutron removal cross sections, neutron angular distributions, and invariant mass spectra were measured, and the contributions from electromagnetic dissociation (EMD) were deduced. Comparison with three-body model calculations suggests that the halo wave function contains a large nu(2s(1/2))(2) admixture. The EMD invariant mass spectrum exhibited enhanced strength near threshold consistent with a nonresonant soft-dipole excitation.
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Affiliation(s)
- M Labiche
- Laboratoire de Physique Corpusculaire, ISMRA et Université de Caen, France
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26
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Axelsson L, Engström AK. The concept of effectiveness--a blind alley? A study of different interpretations in a Swedish county council. Int J Health Plann Manage 2001; 16:61-71. [PMID: 11326575 DOI: 10.1002/hpm.610] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Swedish health care organizations are experiencing pressure to make ever greater efforts to rationalize and to increase effectiveness in the way they plan and provide services. In order to gain a better understanding of the current practice of the three groups of key actors in Swedish health care--politicians, senior civil servants and operational managers--and their perception of effectiveness, a study was carried out in a Swedish county council using both qualitative and quantitative methods. While in general the concept of effectiveness is thought of as crucial, it is not clearly or uniformly defined within the organization. Each of the three groups defines the concept in a way that reflects their own function, which may lead efforts to achieve effectiveness into a blind alley.
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Affiliation(s)
- L Axelsson
- Nordic School of Public Health, Göteborg, Sweden
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27
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Fimland G, Johnsen L, Axelsson L, Brurberg MB, Nes IF, Eijsink VG, Nissen-Meyer J. A C-terminal disulfide bridge in pediocin-like bacteriocins renders bacteriocin activity less temperature dependent and is a major determinant of the antimicrobial spectrum. J Bacteriol 2000; 182:2643-8. [PMID: 10762272 PMCID: PMC111334 DOI: 10.1128/jb.182.9.2643-2648.2000] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several lactic acid bacteria produce so-called pediocin-like bacteriocins that share sequence characteristics, but differ in activity and target cell specificity. The significance of a C-terminal disulfide bridge present in only a few of these bacteriocins was studied by site-directed mutagenesis of pediocin PA-1 (which naturally contains the bridge) and sakacin P (which lacks the bridge). Introduction of the C-terminal bridge into sakacin P broadened the target cell specificity of this bacteriocin, as illustrated by the fact that the mutants were 10 to 20 times more potent than the wild-type toward certain indicator strains, whereas the potency toward other indicator strains remained essentially unchanged. Like pediocin PA-1, disulfide-containing sakacin P mutants had the same potency at 20 and 37 degrees C, whereas wild-type sakacin P was approximately 10 times less potent at 37 degrees C than at 20 degrees C. Reciprocal effects on target cell specificity and the temperature dependence of potency were observed upon studying the effect of removing the C-terminal disulfide bridge from pediocin PA-1 by Cys-->Ser mutations. These results clearly show that a C-terminal disulfide bridge in pediocin-like bacteriocins contributes to widening of the antimicrobial spectrum as well as to higher potency at elevated temperatures. Interestingly, the differences between sakacin P and pediocin PA-1 in terms of the temperature dependency of their activities correlated well with the optimal temperatures for bacteriocin production and growth of the bacteriocin-producing strain.
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Affiliation(s)
- G Fimland
- Department of Biochemistry, University of Oslo, Oslo, Norway.
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Axelsson L, Hellberg C, Melander F, Smith D, Zheng L, Andersson T. Clustering of beta(2)-integrins on human neutrophils activates dual signaling pathways to PtdIns 3-kinase. Exp Cell Res 2000; 256:257-63. [PMID: 10739672 DOI: 10.1006/excr.2000.4816] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The beta(2)-integrins on leukocytes can serve as a signaling unit during cell adhesion and locomotion, and to further clarify this important property we investigated the possible mechanisms of beta(2)-integrin-induced activation of PtdIns 3-kinase. It has previously been demonstrated that clustering of beta(2)-integrins activates p21(ras) by a tyrosine kinase-dependent pathway, and here we show that active p21(ras) interacts with its downstream target, PtdIns 3-kinase. Engagement of beta(2)-integrins also activates the tyrosine kinases p58(c-fgr) and p59/61(hck) and causes them to associate with the p85 subunit of PtdIns 3-kinase. These findings suggest a mechanism whereby p58(c-fgr) and p59/61(hck) are directly involved in the activation of PtdIns 3-kinase. No coupling between p58(c-fgr) and p59/61(hck) could be detected; hence these kinases probably trigger independent but parallel signals to PtdIns 3-kinase. The effect of beta(2)-integrin clustering on PtdIns 3-kinase activity was monitored as the activation of protein kinase B (PKB). Stimulation of PKB by beta(2)-integrins was abolished by genistein and wortmannin but not by using methyl transferase inhibitors to abrogate the influence of p21(ras)-related proteins. Thus, even if PtdIns 3-kinase is not activated by p21(ras), it can maintain full enzyme activity due to the mentioned interaction with p58(c-fgr) or p59/61(hck). These tyrosine kinases apparently activate similar pathways that operate in parallel and therefore have the potential to substitute for each other in mediating adhesion and regulating cell locomotion.
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Affiliation(s)
- L Axelsson
- Division of Experimental Pathology, Lund University, Malmö, Sweden
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29
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Abstract
In order to investigate factors influencing the production of the bacteriocin, sakacin P, Lactobacillus sakei CCUG 42687 was grown in a completely defined medium (DML-B) with 33 components. Although the maximum sakacin P concentration obtained was higher on a complex medium due to higher cell mass, the production per cell mass was higher in DML-B. Sakacin P was produced at 4-30 degrees C, with the highest specific production at low temperatures. More sakacin P was produced at uncontrolled pH compared with cultivation at pH 6.3. Tween-80 had a positive effect on sakacin P production, while addition of sodium chloride and trace metals had negative effects. The decrease in sakacin P concentration during the late growth and stationary phases was shown to be cell-independent and promoted at high temperature and pH. Some differences in production levels of sakacin P were found among six strains of Lactobacillus sakei tested.
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Affiliation(s)
- T Moretro
- MATFORSK, Norwegian Food Research Institute, As, and SINTEF Applied Chemistry, Trondheim, Norway.
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30
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Aasen IM, Møretrø T, Katla T, Axelsson L, Storrø I. Influence of complex nutrients, temperature and pH on bacteriocin production by Lactobacillus sakei CCUG 42687. Appl Microbiol Biotechnol 2000; 53:159-66. [PMID: 10709977 DOI: 10.1007/s002530050003] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effects of process conditions and growth kinetics on the production of the bacteriocin sakacin P by Lactobacillus sakei CCUG 42687 have been studied in pH-controlled fermentations. The fermentations could be divided into phases based on the growth kinetics, phase one being a short period of exponential growth, and three subsequent ones being phases of with decreasing specific growth rate. Sakacin P production was maximal at 20 degrees C. At higher temperatures (25-30 degrees C) the production ceased at lower cell masses, when less glucose was consumed, resulting in much lower sakacin P concentrations. With similar media and pH, the maximum sakacin P concentration at 20 degrees C was seven times higher than that at 30 degrees C. The growth rate increased with increasing concentrations of yeast extract, and the maximum concentration and specific production rate of sakacin P increased concomitantly. Increasing tryptone concentrations also had a positive influence upon sakacin P production, though the effect was significantly lower than that of yeast extract. The maximum sakacin P concentration obtained in this study was 20.5 mg l(-1). On the basis of the growth and production kinetics, possible metabolic regulation of bacteriocin synthesis is discussed, e.g. the effects of availability of essential amino acids, other nutrients, and energy.
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Affiliation(s)
- I M Aasen
- SINTEF Applied Chemistry, Trondheim, Norway.
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31
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Roos S, Karner F, Axelsson L, Jonsson H. Lactobacillus mucosae sp. nov., a new species with in vitro mucus-binding activity isolated from pig intestine. Int J Syst Evol Microbiol 2000; 50 Pt 1:251-258. [PMID: 10826811 DOI: 10.1099/00207713-50-1-251] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A new Lactobacillus species from pig small intestine has been identified. In an attempt to isolate Lactobacillus reuteri strains carrying the putative colonization-factor gene (mub, for mucus binding) a mub-derived gene probe was used to screen pig intestinal material. A number of isolates were obtained and primary characterization showed that they were Gram-positive, catalase-negative, non-spore-forming, non-motile rods. Growth occurred at 45 degrees C but not at 15 degrees C and the DNA G+C content was 46 mol%. Cell wall analysis together with DNA-DNA hybridization and analysis of the 16S rRNA sequence revealed that the new isolates represent a previously undescribed Lactobacillus species closely related to L. reuteri, Lactobacillus fermentum and Lactobacillus pontis. The name Lactobacillus mucosae is proposed for this species and the type strain is S32T.
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Hellberg C, Ydrenius L, Axelsson L, Andersson T. Disruption of beta(2)-integrin-cytoskeleton coupling abolishes the signaling capacity of these integrins on granulocytes. Biochem Biophys Res Commun 1999; 265:164-9. [PMID: 10548508 DOI: 10.1006/bbrc.1999.1645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Integrin-dependent adhesion and dynamic modulations of the actin network are prerequisites for normal cell locomotion. To investigate whether the actin microfilamentous system does play a role in regulation of beta(2)-integrin-induced signalling, we pretreated granulocytes with staurosporine, a well-known protein kinase inhibitor that has also been shown to disrupt the cytoskeleton of intact cells. Pretreatment with staurosporine completely inhibited the beta(2)-integrin-induced Ca(2+) signal and also its ability to trigger actin polymerisation. This inhibition was not related to phosphorylation of the CD18-chain of the beta(2)-integrin, nor to inhibition of protein kinases. Instead, association of beta(2)-integrins with the cortical cytoskeleton, which was observed in untreated cells, was abolished after exposure to staurosporine, indicating that beta(2)-integrin signalling depends on integrin-cytoskeleton interaction. These results suggest not only that the actin network provides an adhesive link to the extracellular matrix and a driving force for the locomotory response, but also that it participates in regulation of beta(2)-integrin signalling during granulocyte locomotion.
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Affiliation(s)
- C Hellberg
- Department of Laboratory Medicine, Lund University, U-MAS, Malmö, Sweden
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Abstract
BACKGROUND The structure and contents of the health and medical service have changed in recent years. The merger of Norra Alvsborgs and Uddevalla hospitals into one local district under one leadership (the NU medical service) is a Swedish example of a structural change. AIMS This study intends to describe and analyse the staff's experience of a recently accomplished structural change in the local district NU medical service in the western part of Sweden. METHODS This study has been carried out from a qualitative point of view inspired by grounded theory. From a theme guide with specific questions, 31 interviews were carried out with staff working in the NU medical service. FINDINGS Four categories emerged from the body of interviews: 'participation', 'doubts', 'anxiety' and 'faith'. 'Participation' was defined as an overall core category, and was related to the other categories. The categories 'doubts', 'anxiety' and 'faith' were related to sub-categories and affected by the overall category 'participation'. CONCLUSIONS The overall results point to the importance of participation of staff members concerned. The role of the leadership when undergoing structural changes is considered as a major factor to make other staff members participate.
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Affiliation(s)
- K Rosengren
- Nordic School of Public Health, Göteborg, Sweden
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34
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Blom H, Katla T, Holck A, Sletten K, Axelsson L, Holo H. Characterization, production, and purification of leucocin H, a two-peptide bacteriocin from Leuconostoc MF215B. Curr Microbiol 1999; 39:43-8. [PMID: 10387116 DOI: 10.1007/pl00006825] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Leuconostoc MF215B was found to produce a two-peptide bacteriocin referred to as leucocin H. The two peptides were termed leucocin Halpha and leucocin Hbeta. When acting together, they inhibit, among others, Listeria monocytogenes, Bacillus cereus, and Clostridium perfringens. Production of leucocin H in growth medium takes place at temperatures down to 6 degrees C and at pH below 7. The highest activity of leucocin H in growth medium was demonstrated in the late exponential growth phase. The bacteriocin was purified by precipitation with ammonium sulfate, ion-exchange (SP Sepharose) and reverse phase chromatography. Upon purification, specific activity increased 10(5)-fold, and the final specific activity was 2 x 10(7) BU/OD280. Amino acid composition analyses of leucocin Halpha and leucocin Hbeta indicated that both peptides consisted of around 40 amino acid residues. Their N-termini were blocked for Edman degradation, and the methionin residues of leucocin Hbeta did not respond to Cyanogen Bromide (CNBr) cleavage. Absorbance at 280 nm indicated the presence of tryptophan residues and tryptophan-fracturing opened for partial sequencing by Edman degradation. From leucocin Halpha, the sequence of 20 amino acids was obtained; from leucocin Hbeta the sequence of 28 amino acid residues was obtained. No sequence homology to other known bacteriocins could be demonstrated. It also appeared that the two peptides themselves shared little or no sequence homology. The presence of soy oil did not affect the activity of leucocin H in agar.
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Affiliation(s)
- H Blom
- MATFORSK, Norwegian Food Research Institute, Oslovn. 1, N-1430 As, Norway
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35
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Abstract
A system for efficient heterologous expression of class II bacteriocins is described that is based on introducing two plasmids in a bacteriocin-negative Lactobacillus sake strain. The first plasmid (pSAK20) contains the genes necessary for transcriptional activation of the Sakacin A promoter as well as export and processing of bacteriocin precursors. The second plasmid (a pLPV111 derivative) contains the structural and immunity genes for the bacteriocin of interest fused to the sakacin A promoter. Using this system, various bacteriocins were produced at levels equal to or higher than those obtained with the corresponding wild-type producer strains.
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Affiliation(s)
- L Axelsson
- MATFORSK, Norwegian Food Research Institute, A s, Norway.
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36
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Abstract
A rapid and simple method to elucidate how intrinsic factors in a given food product affect bacteriocin diffusion and efficacy is described. The basic idea of this assay is to help predict which bacteriocin or other inhibitory substance to select for a given product, where increased security towards specific microorganisms is wanted. In an agar plate model system the effect of five factors (number of indicator cells, pH and concentration of NaCl, agar and soy oil) on the diffusion of the bacteriocins sakacin A, sakacin P, pediocin PA-1, piscicolin 61 and nisin was studied. An experimental design permitting simultaneous evaluation of the effect of all factors was used. The results indicated that each bacteriocin has a characteristic intrinsic factor effect profile. However, pH and load of indicator cells affect all the bacteriocins.
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Affiliation(s)
- H Blom
- MATFORSK, Norwegian Food Research Institute, As, Norway
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37
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Szczepek AJ, Bergsagel PL, Axelsson L, Brown CB, Belch AR, Pilarski LM. CD34+ cells in the blood of patients with multiple myeloma express CD19 and IgH mRNA and have patient-specific IgH VDJ gene rearrangements. Blood 1997; 89:1824-33. [PMID: 9057669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Peripheral blood mononuclear cells (PBMC) from patients with multiple myeloma (MM) are here shown to include 23% +/- 2% of CD34+ cells, the majority of which coexpress CD19, as identified by a panel of 17 anti-CD34 antibodies. The expression of CD34 mRNA by sorted CD34+ PBMC from MM was confirmed by in situ reverse transcriptase-polymerase chain reaction (RT-PCR) with CD34-specific primers. The majority of CD34+ MM PBMC were CD19+ cells that expressed mRNA for CD19 and for rearranged IgH as identified with consensus IgH VDJ primers, as well as having cytoplasmic Ig, definitively identifying them as B cells, in absolute numbers of 0.06 to 0.69 x 10(9)/L of blood. CD34 is largely absent from normal B cells. To determine the clonal relationship of CD34+ B cells to autologous MM plasma cells, IgH VDJ DNA rearrangements of sorted CD34+ MM blood B cells were amplified by nested PCR using consensus primers followed by Southern blotting with allele-specific oligonucleotides for 7 MM patients, and clonotypic IgH mRNA expression was assessed for 4 MM patients using quantitative patient-specific in situ RT-PCR. For 9 of 11 myeloma patients tested, CD34+ blood B cells included IgH gene rearrangements or expressed IgH mRNA identical to that of autologous bone marrow plasma cells. For 4 of 4 MM patients, 74% to 94% of individual sorted CD34+19+ B cells expressed clonotypic IgH mRNA, as detected by in situ RT-PCR with patient-specific primers. Clonotypic IgH VDJ sequences were absent from B cells of unrelated MM patients and of normal donors. Clonotypic CD34+ B cells were detected before, during, and after treatment, and during relapse. Our results indicate a clonal relationship between CD34+ MM B cells and malignant plasma cells. We speculate that CD34 may play an important role in the biology of myeloma by facilitating extravasation from blood and thus spread of myeloma through the skeletal system.
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Affiliation(s)
- A J Szczepek
- Department of Oncology, University of Alberta, Edmonton, Canada
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Elneihoum AM, Falke P, Axelsson L, Lundberg E, Lindgärde F, Ohlsson K. Leukocyte activation detected by increased plasma levels of inflammatory mediators in patients with ischemic cerebrovascular diseases. Stroke 1996; 27:1734-8. [PMID: 8841320 DOI: 10.1161/01.str.27.10.1734] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND AND PURPOSE Leukocytes have been implicated in the development of ischemic atherosclerotic vascular diseases. In a prospective study we investigated whether the plasma concentrations of inflammatory mediators, ie, proteases and cytokines, as markers for systemic leukocyte activation, are increased in patients with acute ischemic cerebrovascular diseases. METHODS Using enzyme-linked immunosorbent assays, we measured the plasma levels of neutrophil gelatinase-associated lipocalin (NGAL), neutrophil proteinase 4 (NP4), tumor necrosis factor-alpha (TNF), and soluble TNF receptor protein-1 p55 (sTNFR-1) in 120 patients with acute ischemic cerebrovascular insult (72 with stroke and 48 with transient ischemic attack [TIA]) and in 35 age- and sex-matched healthy subjects. RESULTS Compared with the control group, plasma NGAL levels were higher in the stroke group (P < .0001) and the TIA group (P < .01); plasma NP4 levels were higher in the stroke group (P < .0001) and the TIA group (P < .01); and plasma sTNFR-1 levels were higher in the stroke group (P < .04). There was significant correlation between the plasma levels of fibrinogen and those of both sTNFR-1 (r = .32; P = .005) and NGAL (r = .40; P = .0001) and between the erythrocyte sedimentation rate and the plasma levels of both sTNFR-1 (r = .35; P = .001) and NGAL (r = .34; P = .002). CONCLUSIONS Our study demonstrated that markers for systemic leukocyte activation, ie, plasma levels of cytokines and proteases, were higher in patients with acute ischemic cerebrovascular disease than in healthy control subjects. Activated leukocytes and leukocytic mediators may have an important role in acute cerebrovascular ischemia and its consequences.
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Affiliation(s)
- A M Elneihoum
- Department of Medicine, Lund University, University Hospital, Malmö, Sweden
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Axelsson L, Borge MJ, Fayans S, Goldberg VZ, Grévy S, Guillemaud-Mueller D, Jonson B, Källman K, Lönnroth T, Lewitowicz M, Manngård P, Markenroth K, Martel I, Mueller AC, Mukha I, Nilsson T, Nyman G, Orr NA, Riisager K, Rogatchev GV, Saint-Laurent M, Serikov IN, Sorlin O, Tengblad O, Wenander F, Winfield JS, Wolski R. Study of the unbound nucleus 11N by elastic resonance scattering. Phys Rev C Nucl Phys 1996; 54:R1511-R1514. [PMID: 9971569 DOI: 10.1103/physrevc.54.r1511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Ohlsson K, Linder C, Lundberg E, Axelsson L. Release of cytokines and proteases from human peripheral blood mononuclear and polymorphonuclear cells following phagocytosis and LPS stimulation. Scand J Clin Lab Invest 1996; 56:461-70. [PMID: 8869669 DOI: 10.3109/00365519609088801] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Release and cellular contents of pro- and anti-inflammatory cytokines, neutrophilic elastase and secretory leukocyte proteinase inhibitor (SLPI) were measured with enzyme-linked immunosorbent assay in peripheral blood mono- and polymorphonuclear cells stimulated with preopsonized yeast cells or lipopolysaccharide. Tumour necrosis factor alpha (TNF alpha) was also measured with a bioassay. TNF alpha production and soluble TNF alpha receptor I (sTNF RI) were demonstrated in the environment of both cell populations. The bioassay indicated levels of TNF alpha far below those detected by ELISA. The overall secretion of cytokines and their inhibitors was found to favour an anti-inflammatory balance in the environment of the stimulated cells. The interleukin-1 receptor antagonist (IL1-ra), compared with interleukin-1 beta (IL-1 beta), dominated the secretions from both cell types with a 100- to 1000-fold excess respectively. Most of the translated IL-1 beta was not secreted but found associated with the cellular compartments. In contrast to lipopolysaccharide (LPS) stimulation, preopsonized yeast cells stimulated a massive release of elastase from neutrophil cells.
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Affiliation(s)
- K Ohlsson
- Department of Surgical Pathophysiology, University of Lund, Malmö University Hospital, Sweden
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Abstract
Divergicin 750, a bacteriocin produced by Carnobacterium divergens 750, preferentially inhibited the growth of strains of Carnobacterium and Enterococcus. Selected strains of Listeria monocytogenes and Clostridium perfringens were also inhibited. The bacteriocin was purified to homogeneity by ammonium sulfate precipitation and sequential S-Sepharose, hydrophobic interaction and reversed phase chromatography. The complete amino acid sequence was determined by Edman degradation. The peptide consisted of 34 amino acid residues. The calculated M(r) from the peptide sequence, 3447.7, agreed well with that obtained by mass spectrometry. Divergicin 750 did not show any sequence similarities to other known bacteriocins. The plasmid-located structural gene encoding divergicin 750 (dvn750) was cloned and sequenced. The gene encoded a primary translation product of 63 amino acids with a deduced M(r) = 6789.4 which is cleaved between amino acid residues 29 and 30 to yield the mature bacteriocin.
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Affiliation(s)
- A Holck
- MATFORSK, Norwegian Food Research Institute, Osloveien, Norway.
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Abstract
A 24-kDa protein was purified from human neutrophil extracts and shown to be the newly discovered neutrophil gelatinase-associated lipocalin (NGAL), based on structural and immunochemical data. A specific enzyme-linked immunosorbent assay (ELISA) was developed for the determination of NGAL in human plasma and tissue fluids. Normal human plasma contains 72 micrograms l-1 of NGAL (range 40-109 micrograms l-1) in two main forms, monomer and dimer. 35S-methionine metabolic studies of human neutrophils showed that granulocyte macrophagecolony-stimulating factor (GMCSF) stimulated significant synthesis and secretion of NGAL in a dose- and time-dependent fashion. NGAL was rapidly released as monomer and dimer on incubation of heparinized whole blood with opsonized yeast, reaching a plateau corresponding to about 35% of total cell content after 30 min. Following intravenous injection of 125-iodine labelled NGAL there was a more rapid initial clearance of the monomeric than of the dimeric form; t1/2 10 min vs. 20 min. During the second phase the two forms cleared at similar rates. Severe acute peritonitis was accompanied by a 10-fold increase in NGAL plasma levels and the NGAL level in peritoneal exudates, which reached about 40 mg l-1. There was a good linear correlation between the concentrations of NGAL, leucocyte elastase and NP4 (neutrophil proteinase 4 = P3).
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Affiliation(s)
- L Axelsson
- Department of Surgical Pathophysiology, University of Lund, Malmö University Hospital, Sweden
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Abstract
Sakacin A is a small, heat-stable, antilisterial bacteriocin produced by Lactobacillus sake Lb706. The nucleotide sequence of a 8,668-bp fragment, shown to contain all information necessary for sakacin A production and immunity, was determined. The sequence revealed the presence of two divergently transcribed operons. The first encompassed the structural gene sapA (previously designated sakA) and saiA, which encoded a putative peptide of 90 amino acid residues. The second encompassed sapK (previously designated sakB), sapR, sapT, and sapE. sapK and sapR presumably encoded a histidine kinase and a response regulator with marked similarities to the AgrB/AgrA type of two-component signal-transducing systems. The putative SapT and SapE proteins shared similarity with the Escherichia coli hemolysin A-like signal sequence-independent transport systems. SapT was the HlyB analog with homology to bacterial ATP-binding cassette exporters implicated in bacteriocin transport. Frameshift mutations and deletion analyses showed that sapK and sapR were necessary for both production and immunity, whereas sapT and sapE were necessary for production but not for immunity. The putative SaiA peptide was shown to be involved in the immunity to sakacin A. The region between the operons contained IS1163, a recently described L. sake insertion element. IS1163 did not appear to be involved in expression of the sap genes. Northern (RNA) blot analysis revealed that the putative SapK/SapR system probably acts as a transcriptional activator on both operons. A 35-bp sequence, present upstream of the putative sapA promoter, and a similar sequence (30 of 35 nucleotides identical) upstream of sapK were shown to be necessary for proper expression and could thus be possible targets for transcriptional activation.
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Affiliation(s)
- L Axelsson
- MATFORSK, Norwegian Food Research Institute, As
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Abstract
Piscicolin 61, a bacteriocin produced by Carnobacterium piscicola LV61, inhibits the growth of strains of Carnobacterium, Lactobacillus, and Enterococcus. The bacteriocin was purified to homogeneity by ammonium sulfate precipitation and sequential hydrophobic interaction and reversed-phase chromatography. The N-terminal amino acid sequence of piscicolin 61 was determined by Edman degradation. The plasmid-located structural gene encoding piscicolin (psc61) was cloned and sequenced. It encoded a primary translation product of 71 amino acid residues, which is cleaved between amino acid residues 18 and 19 to yield the active bacteriocin. The calculated M(r) from the deduced protein sequence, 5052.6, agreed with that obtained by mass spectrometry. Piscicolin 61 did not show any sequence similarities to other known bacteriocins. However, the leader sequence resembled those of the pediocin-like bacteriocins. Piscicolin 61 may be able to form amphiphilic helices and may thus act on the membrane of sensitive cells.
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Affiliation(s)
- A L Holck
- MATFORSK, Norwegian Food Research Institute, As
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Axelsson L, Svensson PG. Setting goals and targets for performance standards within the Swedish health care system. Int J Health Plann Manage 1994; 9:217-33. [PMID: 10137988 DOI: 10.1002/hpm.4740090303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The development of any health care system towards setting goals and targets and intended outcomes--with national guidelines, a legislative framework, limited resources, consumer influence and competitive forces--makes great demands on the control mechanisms required. The Swedish health care system has no tradition of goal formulation of this type. Hence, the purpose of this article is to clarify the goal-setting process of performance standards, and to examine whether goal setting is a relevant method within the organization of a Swedish county council. Goal setting can be seen partly as a control method and partly as an administrative process. The approach used is a combination of qualitative and quantitative methods. Data have been collected from interviews, observations, notes taken in the field and available performance statistics. The analysis shows that working towards a goal is made easier through a common and simple concept. It 'stands and falls' with the management of the work and its manager. Good communications and information are important prerequisites if goal formulation, through dialogue, is to succeed. This process takes time and can be described as an iterative process, in which a common behaviour pattern develops a 'we-feeling' which spreads among the staff. It is important that the goal is relevant and directly related to the basic objects of the work. It is also crucial that the goal is realistic and reflects a priority. Goal formulation relating to performance standards can be a contributing factor to staff's experience of job satisfaction through increased engagement and motivation, and to the satisfaction of patients/relatives with the care given. It is difficult to formulate performance standards; there are many problems and obstacles. If goal formulation as a control method within the health care system in Sweden is to work, clearer manifestations of political will are necessary and also better measuring methods in order to guage achievement.
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Affiliation(s)
- L Axelsson
- County Council of Skaraborg, Skövde, Sweden
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Abstract
Sakacin 674, a bacteriocin produced by Lactobacillus sake Lb764 and which inhibits the growth of Listeria monocytogenes, was purified to homogeneity by ammonium sulphate precipitation and sequential ion exchange, hydrophobic interaction and reversed phase chromatography. The complete amino acid sequence of sakacin 674 was determined by Edman degradation. The bacteriocin consisted of 43 amino acid residues and had a calculated molecular mass of 4436.6 Da, which is in good agreement with the molecular mass of 4437.2 as determined by mass spectrometry. The structural gene encoding sakacin 674 (sakR) was located on the chromosome. This gene was cloned and sequenced. It encoded a primary translation product of 61 amino acid residues which was cleaved between amino acids 18 and 19 to yield the active sakacin 674. Sakacin 674 resembled other known bacteriocins and was very similar to sakacin P.
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Affiliation(s)
- A L Holck
- MATFORSK, Norwegian Food Research Institute, As
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Axelsson L, Holck A, Birkeland SE, Aukrust T, Blom H. Cloning and nucleotide sequence of a gene from Lactobacillus sake Lb706 necessary for sakacin A production and immunity. Appl Environ Microbiol 1993; 59:2868-75. [PMID: 8215360 PMCID: PMC182379 DOI: 10.1128/aem.59.9.2868-2875.1993] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Sakacin A is an antilisterial bacteriocin produced by Lactobacillus sake Lb706. In order to identify genes involved in sakacin A production and immunity, the plasmid fraction of L. sake Lb706 was shotgun cloned directly into a sakacin A-nonproducing and -sensitive variant, L. sake Lb706-B, by using the broad-host-range vector pVS2. Two clones that produced sakacin A and were immune to the bacteriocin were obtained. A DNA fragment of approximately 1.8 kb, derived from a 60-kb plasmid of strain Lb706 and present in the inserts of both clones, was necessary for restoration of sakacin A production and immunity in strain Lb706-B. The sequence of the 1.8-kb fragment from one of the clones was determined. It contained one large open reading frame, designated sakB, potentially encoding a protein of 430 amino acid residues. Hybridization and nucleotide sequence analyses revealed that the cloned sakB complemented a mutated copy of sakB present in strain Lb706-B. The sakB gene mapped 1.6 kb from the previously cloned structural gene for sakacin A (sakA) on the 60-kb plasmid. The putative SakB protein shared 22% amino acid sequence identity (51% similarity if conservative changes are considered) to AgrB, the deduced amino acid sequence of the Staphylococcus aureus gene agrB. The polycistronic agr (accessory gene regulator) locus is involved in the regulation of exoprotein synthesis in S. aureus. Similar to the AgrB protein, SakB had some features in common with a family of transmembrane histidine protein kinases, involved in various adaptive response systems of bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L Axelsson
- MATFORSK, Norwegian Food Research Institute, As
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Holck A, Axelsson L, Birkeland SE, Aukrust T, Blom H. Purification and amino acid sequence of sakacin A, a bacteriocin from Lactobacillus sake Lb706. J Gen Microbiol 1992; 138:2715-20. [PMID: 1487735 DOI: 10.1099/00221287-138-12-2715] [Citation(s) in RCA: 154] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Sakacin A, a bacteriocin produced by Lactobacillus sake Lb706 and which inhibits the growth of Listeria monocytogenes, was purified to homogeneity by ammonium sulphate precipitation and ion-exchange, hydrophobic-interaction and reversed-phase chromatography. The complete amino acid sequence of sakacin A was determined by Edman degradation. The bacteriocin consisted of 41 amino acid residues and had a calculated M(r) of 4308.7, which is in good agreement with the value determined by mass spectrometry. The structural gene encoding sakacin A (sakA) was cloned and sequenced. The gene encoded a primary translation product of 59 amino acid residues which was cleaved between amino acids 18 and 19 to yield the active sakacin A. Sakacin A shared some sequence similarities with other bacteriocins.
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Affiliation(s)
- A Holck
- MATFORSK, Norwegian Food Research Institute, As
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50
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Kulén-Engström A, Axelsson L, Nielsen HC. [Flexible doctors and effective care in consolidated clinics. Interview by Maria Ejd]. Vardfacket 1992; 16:8-10. [PMID: 1502851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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